Document Detail


Pharmacodynamic actions of midodrine, a new alpha-adrenergic stimulating agent, and its main metabolite, ST 1059.
MedLine Citation:
PMID:  66056     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Pharmacodynamic actions of alpha-(2,5-dimethoxyphenyl)-beta-glycinamido-ethanol-hydrochloride (midodrine, Gutron) and alpha-(2,5-dimethoxy-phenyl)-beta-aminoethanol (ST 1059), the main metabolite of midodrine, were investigated in various experimental procedures. Midodrine raises arterial blood pressure both after parenteral and enteral administration in animal experiments. Midodrine increases peripheral vascular tone when given in doses still ineffective in raising blood pressure. The d(+)-isomer of midodrine is by far less effective than the racemic mixture. Pretreatment with atropine, reserpine, guanethidine or hexamethonium has no influence on midodrine activity. Midodrine effects are greatly reduced by phentolamine but rather enhanced by propranolol pretreatment. Midodrine raises blood pressure in pithed rats, too; in the experiments performed the drug is devoid of central effects even when high doses are given. Chronic pretreatment with midodrine over a longer period reduces the effect of a subsequent single injection of this substance. Because of the results cited above midodrine may be classified as a direct peripheral alpha-adrenergic stimulating agent. alpha-Adrenergic receptor stimulation induced by midodrine can be demonstrated in various smooth muscle organs (blood vessels, nictitating membrane, intestine, pupil, urinary bladder, bronchi). In contrast to other pressor sympathomimetic agents, midodrine is of long duration of action and good efficacy after enteral administration. ST 1059, the main metabolite of midodrine, is an active alpha-adrenergic stimulating agent with a shorter duration of action than midodrine. It is suggested that midodrine is the well-absorbed "transport form", from which ST 1059, the actural pressor agent, is formed enzymatically in organism.
Authors:
H Pittner; H Stormann; R Enzenhofer
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Arzneimittel-Forschung     Volume:  26     ISSN:  0004-4172     ISO Abbreviation:  Arzneimittelforschung     Publication Date:  1976  
Date Detail:
Created Date:  1977-04-28     Completed Date:  1977-04-28     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0372660     Medline TA:  Arzneimittelforschung     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  2145-54     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Agonists*
Animals
Blood Pressure / drug effects
Capillary Permeability / drug effects
Cats
Decerebrate State
Dogs
Ethanolamines / pharmacology*
Female
Guinea Pigs
Hemodynamics / drug effects
Hypotension / drug therapy
Male
Mice
Midodrine / metabolism,  pharmacology*
Muscle, Smooth / drug effects
Rabbits
Rats
Vasomotor System / drug effects
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Ethanolamines; 42794-76-3/Midodrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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